Automotive News reported that the crux of the issue is Ford’s claim in mid-July that a 2015 F-450 4×4 Crew Cab pickup can tow 31,200 pounds.

That is 1,200 pounds — about the weight of a good-sized horse — more than the Ram 3500’s highest towing capacity of 30,000 pounds in a 4×2 Regular Cab pickup. So Ford claims the “best-in-class” towing crown for heavy-duty pickups.

But it’s not that simple, thanks in part to the unique way Ford calculates maximum payload.

Ram says the F-450 and the Ram 3500 aren’t in the same class. It says the F-450 is a larger, Class 4 pickup — in fact, the only Class 4 pickup offered by any automaker.

The dispute may seem like just a marketing tug-of-war, but the stakes couldn’t be higher. Towing capability is among the top reasons buyers purchase heavy-duty pickups, automakers say. And heavy-duty pickups represent 23% of total pickup sales in the United States through June, according to TrueCar.com.